Re: TreeView::append_column_numeric() format?

["Murray Cumming" <murrayc murrayc com>]

>> So I would like to add another templated convenience method like this:
>> Gtk::TreeView::append_column_numeric(TreeModelColumn& model,
>> numeric_format);
>>
>> But what's the best way to specify the display format for the number?
>> I'd
>> rather not use that nasty printf() style format. Does C++ have something
>> more suitable?
>
> Boost has a "format" object (described here:
> http://www.boost.org/libs/format/doc/format.html)

Using a formatter object is a good idea, but it seems to mostly use the
sprintf format anyway, with some extensions.

Also I would feel bad about reproducing so much code in gtkmm. And we
can't depend on boost because it's not a stable (API or ABI) library yet.

If we find no better alternative to the sprintf format then we could just
decide to live with
  TreeView::append_column_numeric(TreeModelColumn& column, const
Glib::ustring& format);
where format is something like "%.4f" for 4decimal places.

> I'm not suggesting that this actual class should be used, but it's a
> starting point for ideas. The Gtk::TreeView::append_column_numeric()
> method could take an object that formats a number (perhaps with a number
> of
> simple/common ones supplied). I don't know how all this works underneath
> though, does it need to translate to printf format for the Gtk+ interface,
> or does all the formatting happen in the C++ wrapper?

Gtk+ has no equivalent for this. Their whole GtkTreeView API is much more
unpleasant. And they are probably happy to use C-style sprintf formatting
for this.

Murray Cumming
murrayc murrayc com
www.murrayc.com
www.openismus.com